WASHINGTON (AP) — The Secret Service is investigating news reports of other trips in which employees allegedly engaged the services of prostitutes while traveling abroad in advance of the president, an agency official said.

The official, who spoke on condition of anonymity to discuss ongoing investigations, said the agency is trying to determine whether the reports are accurate.

Seattle television station KIRO-TV reported Wednesday on allegations that during a trip last year to El Salvador, agents engaged in activities similar to those in a prostitution scandal that emerged after a presidential trip to Colombia.

The report came hours after Homeland Security Secretary Janet Napolitano told lawmakers that what happened in Colombia was an isolated incident and that it would surprise her if there were a broader problem.

The Colombia scandal erupted the morning of April 12, when a fight over payment between a prostitute and a Secret Service officer spilled into the hallway of the Hotel Caribe. Since then, a dozen Secret Service employees, including two supervisors, and 12 military personnel have been implicated.

Eight of the Secret Service officers have been forced out, the agency is trying to permanently revoke the security clearance of one, and three others have been cleared of serious wrongdoing but will face administrative discipline.

One of the Secret Service officers was staying at the Hilton hotel in Cartagena, Colombia, the same hotel where President Barack Obama later stayed for the Summit of the Americas.

Little is known about the fate of the six Army soldiers, two Marines, two Naval personnel and one Air Force airman, though Defense Secretary Leon Panetta said this week that all have had their security clearances suspended. A 12th serviceman, assigned to the White House Communications Agency, a military unit that provides security communications for the president, has been relieved of his duties at the White House.

Napolitano’s testimony before the Senate Judiciary Committee Wednesday was the first public questioning of a Homeland Security official since the tawdry affair became public.

She said the agency’s Office of Professional Responsibility had never received previous complaints in the past 2 1/2 years, but it was unclear why she specified that period.

The chairman of the Judiciary Committee, Sen. Patrick Leahy, D-Vt., praised the Secret Service as “wise, very professional men and women” and called it shocking that so many of the agency’s employees were involved in the scandal.

“It really was, I think, a huge disappointment to the men and women of the Secret Service to begin with, who uphold very high standards and who feel their own reputations are now besmirched by the actions of a few,” Napolitano said.

Napolitano said if the misconduct was a pattern, “that would be a surprise to me.”

The Seattle television report also included allegations that U.S. embassy officials and officers from the Drug Enforcement Administration and FBI have routinely engaged the services of prostitutes in San Salvador.